Lecture 36 : Environmental Acoustics

So, ah, welcome buddies welcome pupils currently,
where in the eighth lecture the 8th week lecture and also the, this last week ah, we have
ah, kept the module on the Environmental Acoustics. So, in this module in the five segment of
those lecture begins from the lecture number 36 which will deal with the Environmental
Acoustics. One will certainly most likely to the Setting Acoustics,
2 in the next lecture and afterwards we will go to the, some urban noise and the the, the
several of the the, the dealing with the city sound and the the mitigation of the sound
. So, ah, as normal will certainly start with the, the learning purpose. So, right here ah, the we will certainly
originally categorize the different kinds of ecological noise and afterwards will review the, the effect
of the sound as well as a few of the measurement techniques as well as the dimension indexes. The very first one
is which can be found in our mind is that what is the noise; sound is in fact an undesirable noise
It has typical three criteria if the sound
. is really loud then it is the unwanted in that method as well as in some cases it is, sometimes it is the
un ah, ah, wanted incense of this unmusical kind of an audio which can not produce, that
type of a sensation, that sort of an interest in our mind or interest in our mind.So,.
that a typical noise will be dealt with as a noise kind of a thing. So, it is again a, ah, significantly subjective criteria, but ah, despite the fact that if it is a subjective.
requirement, there are some type of qualities? In this criterion, where the ah, the size.
of the noise as well as the period of the sound as well as common regularity of the noise and likewise.
the when its certain sound is actually mosting likely to be happen the time of occurrence is.
very crucial ah, to ah, find out about that particular or the court regarding that particular.
sound is a noise or a music. The actually the opposite word of the noise.
may be a songs which ah, we can treat as a subjective one constantly and also ah, the desired audio.
or the noise we make like to below can be treated as or specified as a music as well as which.
is not at all wanted or not in all favored for hearing or can not create any type of sort of passion.
in our ah, mind or in my our mind or in our sensation is called noise. So, ah, many of the time if you can go to a ah, outdoor or perhaps if it is if you walk.
in the metropolitan area or possibly a municipality or might be any area where that this is exposed to.
a great deal of noise as well as if you see the that certain character of the nose is in fact ah, ah,.
typically makes up of different frequencies of the audio as well as additionally ah, the wearing of decibel.
levels also.So, I have drawn here a specific contour or.
the sinusoidal curve which is significantly uneven in shape and also which is significantly going to be.
a regular in nature and also in another one which I have actually drawn which is which is ah, usually.
routine ups as well as downs. The; the change of the audio variation.
of the pressure is additionally distinguishing which is also a propagation of the audio, yet ah,.
there is a difference in between this eco-friendly shade graph as well as this red color graph the red color.
ah, chart is very much scattered or quite ah, on ah, ah, and hm desired in that sense.
and it is really much you can claim unsure after that when it will be an optimal as well as when it will.
be an one more believed those type of a scenario.So,, due to the fact that

of this particular second graph.
is a mixed of a complicated tone and there is lack of the harmonics and also the octaves as well as.
it is a very on consistent in character hm, from the amplitude point of sight and as you understand.
the, the amplitude varies the differential presser level will exist or the differential.
d b degree will be there. So, these can be dealt with as this sort of a.
spectrum as ah, or the sound range can be dealt with as noise where as if it is a a.
facility tone, yet it is a more of harmonics and also the octave, which gives a sort of a smoother. The repeated kind of a regular contour and a steady character of the particular contour.
from the the the, the, the amplitude and also this specific amplitude and also the frequency point.
of sight it says, the music or which, which is it may intend to hear. So, next comes the noise pollution, because sound air pollution is significantly related to the.
metropolitan noise as well as sound pollution is just one of the, the, the prime variable nowadays every,.
every citizen of the the, the ah, country in our nation as well as additionally in the various other nations.
quite trouble about and ah, the what is the environmental pollution? It is a the its kind of an environmental ah, ah, reason which as a result of the audio and also that.
is a kind of a given sort of an endangering to the health and wellness of the human and likewise for the.
the, the pet occupants ah, as a result of the ah, not only ah, from the d b degree ah,.
is the one of the criteria hm.Ah, it is the, it is a sort of a requirements,.
it is not just the d b level, however also the the, the, the certain regularity in developed.
in it and also the rep of that certain regularity is ah, silently unstable type of.
a think as well as produce a ah, type of a sound, because ah, if I provide example a guitar give.
you music and if I begin playing guitar sometimes, it may be a noise to you, since I do not.
recognize how to play guitar. So, ah, ah, if I play then it will be various frequency ah,.
unsteady way it will certainly adhere to as well as then that can be a noise, but we can not might be endure.
for a, ah, the even more than minute also. So, sound contamination is actually linked.
with the outdoors ah, ah, circumstance or that is called as an outside ah, noise as well as that.
are ah, having different the reason or the various resources will review in every detail.
of that.So, out of the reasons is the sector neighborhood building and construction and also transportation.
field is the, the major source of the, the noise pollution. Next, allow us most likely to the urban noise, there is ah, very ah, not significantly considerable.
adjustment in between the environmental pollution and the city sound is worried. The sound pollution.
is that if you are ah, the specific noise level is above a certain particular limit.
ah, which was recommend by several of the, the pollution board additionally which is can, can be.
work as or can be ah, endangering to the health and wellness which can be dealt with as an environmental pollution. Whereas, in instance of the city sound there are some locations which may be a type of a polite.
among kind of frustrated which might not go ah, beyond that specific limit as well as sometimes.
it may go often it might go in the night time occasionally might enter a certain period.
of the day. So, there are great deal of ah, ah, the parameter.
related to the those activities the metropolitan tasks as well as all and also due to that specific.
tasks, there are resource and also there is ah, type of a the the, the ecological.
sound has been worried or has been the regarded which particular act.Ah, the, the noise.
which is ah, activated by some sort of a city activities are ah, in a in a bracketed.
term in a domain terms called the, the urban noise. So, ah, what is our ah, primary worry is that in our lecture in the ah, successive lecture.
of this last component is that ah, exactly how to investigate effective; properly check out that specific.
sound as well as we need to actually understand about the sources of the metropolitan sound and also, we require.
to know the, exactly how you need to alleviate the those are lower this particular noise urban.
sound. So, in that we have ah,; we can have this.
sort of a circulation diagram as well as let us know what are the the, the, the regular the circulations and.
the parts of an urban noise reduction techniques. The initial one we should know of.
the ah, understand about the metropolitan sound source as well as the effect of the metropolitan noise. This is.
very a lot crucial some source might not provide any type of type of effect which is impact I am chatting.
regarding the which is significantly ah, endangering to the the, the, the the, health and wellness of a specific.
human being or might be an animal.So, ah, sometimes a particular resource perhaps.
having a very high effect. So, we need a type of a noise measurement strategy which.
is really important to recognize in between the relationship between the resource of the sound and also the impact.
of the sound and after that there are some criteria which criteria are actually affecting. The; sometimes it is mosting likely to ah, the add or sometimes, it will be mosting likely to offer some.
kind of advantage towards the propagation of the noise and also in some cases those criteria.
are really mosting likely to rages this certain noise. So, it recognize, concerning those criteria which and also ah, we need to in fact in style that.
particular, certain built environment such away ah, the resistance- specification are ah,.
possibly boost as well as that can be lowered the quantity of sound or the ah, metropolitan sound.
and ah, based upon that only I have actually already informed based upon this those criteria on, on,.
just this, this noise decrease techniques can be considered or can be carried out. Now, as we have to recognize about the various resource of the noise.So, let us

first ah,.
speak about some sort of the, the sound which is called as a I imply the. So, different ah,.
classification of the metropolitan sound as well as the first one is the traffic sound each one of.
you are in fact subjected to this is, is a noise which comes from the surface area transportation.
ah, mainly from the road train and also the possibly some kind of the aircraft activity likewise the.
second it has actually. So, ah, regular sub departments or category.
second one is the industrial sound which originates from the workshop in the type of a sector.
plant and all, because of the activity as well as the operation of those sector the third.
one is called the building and construction sound which is occasionally very-very bothering in the sound,.
originates from the construction tools like hammer jack stack ah, ja ah, ah, jack hammer.
and the pile motorist concrete mixer and also great deal more.And ah, those that are actually ah,. ah, the stay really close by those buildings ah, the task locations maybe for several years or. two years additionally. It is really often bothering the 4th. and also last one in this category is called the neighborhood noise which is in fact a sound.
generated by a neighborhood which are the street sound, noise from the any type of gatherings perhaps.
it is a social gathering or may be a political celebration some kind of a rally or some kind.
of a the the, the chi noise from the youngsters. They are playing in a ah, specific park.
or perhaps an institution whatever and the speaker sound from ah, any particular area after that some.
type of a ah, comes something like a barking of a constant barking of a canine or those.
sort of a points ah, it is really bothersome while in the, the night times if the.
canine barking for a long-long period. So, those are, needs to also dealt with really.
very carefully Currently, allow us most likely to the first one that is a.
website traffic or the road website traffic sound and ah, there are various ah, ah, considerable ah,.
the, the quantity of ah, the sound is create in the roadway and its in fact the among the.
the, the significant source of the sound pollution in any kind of city or any type of city location ah, it is, there.
are ah, ah, various root cause of this part expect if you take an automobile, if you take a car.
or if you take a truck or if you take a, ah, kind of a bus. So, ah, there are different ah, sound generating ah, EQU ah, the, the part device there.
are, the exhaust there are some type of a the yeah, the engine follower as well as those tires and also.
ah, likewise it is rely on the rate of the certain lorries additionally, but it actually.
rely on a number of ah, various other variables, like the what is the, the roadway problem. If the road condition is good certainly the amount of noise created by the website traffic or.
may be by the lorry will be much less the, the congestion of the website traffic, the traffic clearance.
as well as all those type of a points are likewise developing a noise.If the there is

nearly this attire. speed preserving in a particular course of road the quantity of noise once more, will be going.
down the ah, the abrupt damaging an all those points in fact create the noise the. So, sort of breaks and all, the problem of the vehicle is another one the rate of.
the car is an additional one ah, and also as you understand the speed of the car if it is an.
raised ah, sound is not proportionally, however ah, some what it is raised there are.
driving guidelines and also keeping an eye on systems are also ah, as a may be the, the in straight parameter.
that raise the metropolitan sound or the metropolitan road traffic sound and the last one is not.
the checklist its the good sense of people or the citizen is additionally among the ah, the, the.
among the vital factor which contributes in the is domain name. Ah, as well as in the case of the, the railway website traffic ah, there are once more, there are some ah, the.
elements which comes from a certain resource itself that is a train itself ah, that is.
the diesel exhaust engine cooling fan etcetera.The wheel rail

fiction, that is one more one.
which create some kind of irritating audio electric motor which really drive the train. The siren horn breaking system every little thing ah, which is the ah, each one of each one.
of those are the integral part of any type of sort of a ah, train system or the railway mo,.
motion understand which is going to offer some sort of a noise as well as various other then that the, the, track.
ah, track to onlooker range, that is one track length is another one the quantity of.
load in trains of specifically for the products train or the freight. Ah, train suppose an items train is empty often it is noisy if it is not empty it is full.
after that may, might not be loud its in some cases not that lower the lots is significant after that the noise.
is more no often less.The empty

vessel seems much all of us recognize ah, and the various other,.
other conditions are the a few of ah, some of the problem of the track and in some cases.
the condition of the instructors as well as everything likewise import. Some sort of a noise air traffic sound this is a 3rd component of the, the transport.
sound is worried ah, it is actually depending upon the rate of the air web traffic as well as the.
range and the, the distance from the observer to the source ah, because of ah, the traffic.
the air traffic as well as air steep in a certain location ah. It is depending upon the what is the distance from the resource to the observer and also in time.
of if it is, if it is very near to if the, the receiver, receiver the onlooker is very.
close to a the, the airport then it is the, the removing and the landing time the air.
aircraft creates the much sound are which sometimes unbearable.Yes, supersonic

jet. planes if it is an extremely high range also from an extremely high distance additionally its extremely.
high level of noise will enjoy produce occasionally ah, it is may damage the windowpanes and also it.
might ah, ah, some minor cracks may appear in the very ah, the structure walls and all, since.
of that sonic ah, wave proliferations also. Then following ah, comes the industrial noise we.
already talked concerning that as well as those are the regular ah, various component of the activity.
or ah, the with different stage of the industrials activity which in fact generate some kind.
of the industrial noise that includes the some running makers hammering grinding. Then lathe works the steaming steaming job, likewise see the following one is the building and construction.
sound which once again ah, is ah, depend upon great deal of building and construction tasks an, as you all.
know, that the every single building and construction stage required some sort of a guidebook or perhaps.
some type of a tools for operation as well as its ah, it is not silent procedure its offers.
you a kind of a ah, noise and its actually.So, when it is

in fact ah, the area which.
is surrounded by those the building and construction activity is susceptible to the, those sort of construction.
sound as well as ah, its really ah, the people that are remaining in a newly creating or the.
upcoming location is mostly impacted by this building and construction sound and also those are the checklist which ah, can.
create a very aggravating sort of a noise in building tasks the earth relocating work.
the demolition of some existence structure. Ah, driving of the heap is very-very monotonous in noise point of sight ah, concrete mixer.
pumping of the concrete the any type of, any sort of the welding, welding is possibly a kind.
of a little bit of quiet process, but the riveting and also the, the following one is a hammering is ah,.
extremely ah, bothering ah, it is from the sound perspective. The last one last, yet one that is the cutting of floor tiles ah, is another one which is ah, generate.
a great deal of really high frequency sound and which is a ah, extremely high degree the from the, the.
d b degree factor of view.It is very high as well as likewise really much ah, effecting I mean the ah,. the physiologically or might be the emotional it is quite impacting if you mean.
a quiet a one minute also it is may not be intolerable often. Then the community sound ah, it is the component of the community part of the task in the.
area ah, and because of that of this community sound likewise, in some cases our sound judgment is.
accountable yes and ah, the enforcement authority are ah, might not be really should rigorous as well as they.
permit people to run the loudspeaker in the very allow night or which play a create a trouble.
to the, the individuals ah, like the, the elderly individuals, individuals with illness the kids as well as baby.
and all.So, ah, those are the sum of the tasks.
I have actually already told you ah, the, the those are the, the area sound ah, factor of.
sight. And there are, some impact ah, ah, of the noise I informed you in the very start. The sound pollution has actually specified as it is something ah, above some sort of a standards of the d.
b degree standards and which provides you a sort of an unsafe effect in a, ah, particular human.
health.So, its ah, there are 3 kinds of human.
wellness based on the who ah, has actually stated that its some kind of a auditory which is the hearing.
loss and also the limit of ah, shift sort of a scenario can be occur, there is a mental.
which is a stress ah, there is a metabolic adjustment there been hormonal modification likewise. There.
may be a some kind of a gastric problem as a result of the, the if you are revealed to really ah,.
longer duration in the loud atmosphere. There will be a behavior adjustment if you are.
ah, susceptible to a loud environment long duration like might be a ah, month or more than.
that then there might be a modifications in the regular behavior pattern ah, primarily it is have actually been.
loaded in the wild life, but likewise it has been loaded in the people that are subjected to the.
commercial noise and also the transportation noise ah, in a longer duration period ah. Next, the specifications we have actually already talked concerning there are some specifications which would certainly.
going to influence disagreement in a breeding of the, this the sound which is the, the metropolitan.
noise the its the resource geometry and also the kind it is an one of things that is the.
point line actions coherent and also the fundamental type of a criteria. The atmospheric problems there wind temperature level the, the flow of the wind and the the the,.
the rate of the wind is additionally going to be an issue ah, the breeding of that certain.
sound climatic absorption of the sound which is because of maybe some sort of a humidity.
or some type of a various other ah, put on hold matter in this ah, readily available in the air the surface.
type and also the shapes ups and down hilly areas.So, they are can be some sort of the the noise. protecting area sound shadow zone and the lastly, it is some sort of a blockage this may. be a manmade obstruction.
There might be a type of a in natural blockage, obstruction by. the vegetations likewise. So, that also can
help occasionally propagation. Next one is the measurement of the sound. So, I have simply examine down several of the the,. ah, ah, situation details as well as likewise the, the positioning of the tool according to the the, the instruction. of the central air pollution control panel Delhi ah, this is CPCB.So, they have actually mentioned some. kind of the criteria ' s

construction tools

ah, mean if you are taking some type of a'audio for any d. g set that is the diesel generator collection or possibly any kind of devices it is one meter from the. distance, from the all the side as well as ah, if it is more. So, about 1-meter distance from the acoustical enclosure, we need to take the measurement. for any kind of kind of a fire biscuits which is again, one of the concerned
ah, at some point supreme. court state some type of a the, the rules or the ah,
kind of a guidelines for that. So, for that particular dimension of that certain sound, the blowing up noise of the. fire biscuits, it is 4 meters from the blowing up factor has actually to be taken as well as hm. There should. be the, the ought to not be any type of kind of a reflective surface around the 15 meter of the.
distance that is around the requirements or, because if there is a reflective surface area, the overall.
quantity of sound really tape-recorded, because certain microphone will certainly be significantly high
.For any type of sort of the lorry for the roadway noise
measurement 0.5 meter from the exhaust point of the lorry has to be taken.It is extremely

close to that specific an exhaust point of the car has actually to be taken and the microphone point must be positioned at around 1.2 to ah, 1.5 meter ah, which is virtually around 5 feet 4 to 5 feet level above of the ground which is basically of our ear ah, level also as well as ah, in situation of it has actually to be absorbed the completely dry problem, since their you recognize that the wind velocity likewise plays essential function. So, any kind of problems, which we need to be the wind much less than 5 meter per 2nd velocity need to be ah, the that ought to be the standards of the measurement and also this tool need to be without any kind of kind of the vibration or any kind of a shock. So, ah, if and also as we understand this particular sound is having an incorporated regularity and likewise quite of combined the, the degrees d b degree expect some resource gives you some d b level l one after that a few other source offers l 2 l3 like that. So, we can not evaluate each one individual, we need to provide a come one particular the, the number which is can be a either it total sound degree or possibly an average sound level this is the formula to determine the the overall noise degree if there are n number of sources provides you the l 1 l 2 l 3 as well as l n.So, those are the ah, the l 1 by 10 and also this 10 to the power that, has actually to be added arithmetically which has actually been log logarithmic of that and has actually be increased by 10 will be the easy means to figure out the, the l totals the total ah, noise level of a particular ah, the area for a particular immediate problem. Actually this 10 to the power l 1 by 10 is nothing, yet the, the intensity of a ah, the particular noise because particular time or ah, ah, that certain ah, source of which is in fact generating l 1. Yet there is typical ah, noise degree likewise which just that which I have included the really ah, the various other slide the previous slide, we need to divide this by the complete variety of resources n. So, expect this is originates from a bus this one is coming from some type of a, ah, some ah, road note for some type of an one more resource this is some kind of a shop maybe it in the stretch of a ah, road.So, there are 3 such resources ah, and afterwards you split that by 3 as well as take the logarithmic of that as well as after that multiply by n. So, this is the average of the noise standard ah, the typical noise level of the particular ah, sector of the road for a particular sector of the certain motion on when you are considering that particular ah, reading. So, I have a tiny ah, tiny, example for you I have five sources expect in a roadside as well as or perhaps it perhaps a kind of 5 machines that produce ah, the noise in a particular industry and one the very first one offers you 75, the 2nd one 30, 50, 90 as well as 65 like that.
So, this is by 10 is 7.53 then 5 9 as well as 6.5 and also 10 to the power of that is this and I.
have added it up as well as number of examples are n is 5. So, if I currently want to discover the overall. So, need to logarithm you have actually taken take of the.
log of this entire large number and also after that multiply that by 10 which offers me nearly about.
the ninety d b is the, the complete noise degree, but if I desire to learn the standard have.
to split this, separate this by 5 after that ah, divide this this large number 5 that is the.
and after that I take the logarithmic and afterwards increase by 10 as well as I will certainly get bit much less little less.
quantity of as a typical noise degree average 83. So, ah, what I discover from below is that the l total amount is always going to be bit higher.
ah, from the typical point of sight, yet is not the simply the, this actual the, the fifty percent.
of that not not such as that it is a sort of a little less than the, the average little.
less, than the complete again.Again, there

is a the really ah, ah, among really basic.
ah, the standards which is available in our mind is that the human hearing system is not just as.
sensitive to all the regularities as you all recognize. So, ah, if I simply take that typical ah, if I take all this heavy ah, this specific.
total amount of all the frequencies ah, of all the, the l 1 l 2 l 3 all well audio stress degree

It may not provide you the actual sign of the noise or real indicator of the total amount.
sound or the average sound. So, for that a modification has been produced.
various octave band frequencies as well as those octave band adjustment lastly, gauged in.
a, ah, ah, I imply this change is called A a weighting change there are B weighting.
additionally C weighting also, but the a weighting change are the measurement are quite.
ah, the ah, significantly reliable for our sound estimations and environmental sound estimations.
and all and also just how it is can be done.We can simply give you a, ah, type of a statement is.
that, there are 10 octave band and also for this octave band this modification is offered in d.
b. So, intend ah, you have and also this improvement.
these are mainly in negative modification. So, if you have some decibel level for 31.5 corresponding.
to 31.5 with their top and reduced band if you remember we have an octave band which.
is edge and also reduced hand that is the upper reduced band within that if any kind of frequency comes.
which comes under the31.5 you have to subtract 39.4 d b from that, because those low regularities.
not that much smartly in our mind. Suppose, something is with an around in an.
around 2000 frequency then you need to add 1.2 frequency whatever possibly your recording.
from the d b meter you have to add 1.2 decibels. If it is 1000 in an around 1000, you need.
not to do any kind of a correction. So, mainly you see there are adverse corrections and.
there are only for 2000 and 4000 there are some favorable increment. So, if I take an an additional instance suppose I have majorly specific band of regularity.
in a noise for a certain moment in a particular ah, roadway ah, or might be industry or might be.
any type of area and also if I examine that specific spectrum of the sound I located 31.5 ah, the.
hertz audio majors contribute nearly about 60 d b 63 55 is 125 hertz sound in an about.
is 35 d b also something like that all the 10 frequency 10 octave band regularity these.
are given.So, I want

to figure out the what is the, a.
heavy range. So, I can not simply ah, take the previous formula and also just calculate and also.
that I can ah, figure out the total, however that will certainly not be the actual reflection of the real.
representation of the, the sound in fact we below. So, we require some type of an improvement. So, those are the 60s to 40 which is in the offered.
in the, this certain slide ah, measure I mean, I have actually put over in this certain.
column second column. This is the octave band and also these are the improvement factors.
price or that this purple colours or the negatives as well as this environment-friendly colours are the favorable. So,.
if it is 60. So, if to60 minus 39.6 is 20.6 39 as well as 55 minus.
26.2 is 28.8 something like that if you take the adverse I imply if take ah, the subtract.
from this to that 75 does not have any modifications it will stay as75. 60 is plus 1.2, 61.2.
254 is 45e plus 146. So, you obtain the dealt with d b level.So,.

even a particular located in a roadside which is having a31.5 ah, regularity which determines.
as 60 d b real properly it is hm, it is influence in our in our brain according to the,.
a heavy scale is 20.6 d b additionally that that that this will certainly improvements stays that. And also.
currently from that this column if located that l by 10. So, this is 2. nothing 6288 like that and after that to the power of that. So, this huge numbers.
and I accumulate this large numbers. So, is a large number and after that this large number is.
log the logarithmic of that huge number in multiplied by 10, is the that is the.
formula for the l total.So, I will certainly

create this as a 79 I discovered it as a 79.6 and also when.
I write it I will not create d b I will compose d b a why a A, because it is a heavy range
. So, any type of ah, environmental sound is really.
weighted in a range ah, the a weighted range and ah, finally, ah, as you know if I just.
if I do this ah, this logarithmic of the enhancement where the l overall with the 2nd column which.
is actual analysis can have been much-much higher ah, there can be a kind of a complication.
there can be type of a ah, relative ah, the higher worth we will certainly get. So, to prevent that sort of a complication as well as stay clear of that kind of a reasonably greater values.
in our computations or in our understanding a weighted range is has been proposed as well as.
lastly, we will compose that particular system as a, ah, d b decibel a weighted a, so, that.
is ah, the, the, completion of this lecture of lecture number thirty ah, 6 ah, which talks.
about the Environmental acoustics component one.So, ah, as I have some homework for you like.
other talks ah, ah, allow us initially separate between the music as well as noise ah, what you comprehend.
from your ah, I imply the understanding of this particular ah, lecture and from your.
very own understanding on the songs and also noise ah, exactly how you can distinguish of in between those.
in between these two terms ah, may be literally or perhaps incase in instance of some goal.
interpretation wise or possibly any type of sort of a subjective method. The second one is additionally ah, intriguing as well as additionally really much needed to understand I mean the.
what is the actual the distinction in between the total sound intensity level which is I.
have revolve ah, l toddler [al] l total amount as well as a weighted level and why ah, these two are called for and also.
why ah, what are the, the significant ah, distinction between these two this is the one.
as well as the, the second research for you is that expect I have 3 sound information ah, one is.
80 d b one is 50 d b 165 d b. Ah, if simply locate out the what is the total.
sound degree and the typical noise level, as a result of this 3 sources hm ah, if I ask that.
what is the, a heavy noise level for this particular second trouble or second assignment.
or the 2nd research ah, it is very huge, because you can not in fact figure out because.
why, since I need to offer ah, the equivalent frequency exactly how much is which regularity contribute.
eighty which frequency add ah, 50 or 65, since ah, base based on that without.
frequency can not go for the a weighted, because ah. If you know the regularity and corresponding ah, the l value that is the degree value and also.
after that can you can apply those adjustment and after that you can go with the including or amounting to.
of that.So, I have taken some help from those books excellent publications and likewise ah, 2 such.
ah, ah, I indicate the, the resources one is the this CPWD. I am sorry ah, CPCB ah, central pollution control panel their ah, some files which.
is one of the method for the noise monitoring and also for the aircraft sound kind of a point.
that also they have actually given in their web site as well as likewise the extremely new one, this is the national.
developing code 2016 quantity 2 handle the acoustics and the noise ah, this is ah, those.
are the some ah, ah, the sources I have actually taken aid for this certain lecture you can additionally.
undergo ah, that is all for this particular lecture. Thank you quite …

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